What stem cell first develops in blastocyst

The tubes transporting minerals and water upward are called ?

Can bacteria reproduce in a way such that when you start out with two bacteria, you get five bacteria? why or why not? * a. yes, because bacteria reproduce sexually, and can produce any number of offspring, just as humans do. b. no, because bacteria grow at an exponential rate. c. no, because when bacteria reproduce, they split into two parts, and two bacteria splitting would result in four bacteria.

Is there any species that went extinct in recent years due to natural causes (not caused by human interaction). if so, what caused it?